A new period and period changes in VZ Hydrae

Abstract

A new period (P=2.ͩ9042997) of the eclipsing binary system VZ Hydrae has been given, which is based on all the available times of minima. The period based on the photoelectric epochs has also been presented. The O-C diagram and detailed perod study of VZ Hya have been presented for the first time, and the period changes have been estimated in different portions of the O-C diagram. Significant period changes do not appear to have occurred in VZ Hya, however, the O-C diagram suggest that the period of the system shows a slow tendency to increase. Period changes of 10⁻⁵d(?) to 10⁻⁷d have occurred around the years 1933, 1971, and 1975. All four period changes are noted in the time-interval 1918 to 1978. Upward trends appear stronger than the declining trends. Secondary minima show larger fluctuations than the primary minima. The fluctuations of the O-C values around the zero-line of the VZ Hya demands notice for searching out the cause of period variations such as the presence of a third body.